Botanists and agronomists are continuously developing new and improved varieties of tomatoes for commercial processing. Typically botanists and agronomists seek to develop tomatoes providing higher yield per unit area of growing space; that is, more tomatoes of greater weight per vine or per given space in the field. Additionally, botanists seek to develop tomato varieties having improved resistance to wilt and other funguses, improved resistance to drought and to excessively wet conditions, improved resistance to disease and to insect infestation and in which a high percentage of the fruit ripens at the same time.
Unfortunately, while botanists have developed tomato varieties for commercial canning purposes having the aforementioned improved characteristics, these newly developed tomato varieties demonstrate strong adherence of the ripe fruit to the tomato vines, making the ripe fruit difficult to harvest mechanically. This is especially true if the growing season has been dry. Currently many of the most popular commercially grown tomatoes, including many tomato varieties which are specified by commercial canneries and food processors (farmers growing tomatoes under contract for such canneries and food processors must grow the specified variety) are varieties which exhibit substantial and effective strength where the ripe fruit attaches to the tomato vine. These varieties of tomatoes are appropriately called "hard to shake varieties" in the trade and include popular commercial varieties whose seeds are identified as "7151 Heinz" and "1810 Heinz" specified by H. J. Heinz Foods, Inc., as "8245 Ohio Seed" developed by Ohio State University, as "U.S. Seed 68" developed by the United States Department of Agriculture, as "UC 82 B" developed by the University of California and as "696", "1596" and "2196" all developed by and available from Peto Seed Co., Inc., in Santicoy, Calif.
Current commercially available tomato harvesting equipment, when used to harvest these "hard to shake" tomato varieties, customarily leaves from about 3 to about 5 percent by weight of the fruit of these varieties on the tomato vines, when operating under conditions typically encountered in the northeast, southeast and mid-west sections of the United States.